Preparation of Transparent ZIF-8/TiO2 Nanocomposite Thin Films for Photocatalytic Applications

Abstract

Transparent ZIF-8/TiO2 nanocomposite thin films were prepared by a two-stage dip-coating method. TiO2 was first deposited on glass substrates by sol-gel dip-coating. Heat treatment temperature, number of layers and doping metal type/level were optimized in the first step. In the next step, ZIF-8 was grown by solvent based crystallization method on TiO2 layers. Cu, Ce, Fe or Zn doped TiO2 thin films were prepared in order to increase the photocatalytic performance of ZIF-8/TiO2 nanocomposite. The highest photocatalytic methylene blue degradation activities were obtained with the ZIF-8/TiO2 nanocomposite thin films prepared by using 1% Cu or 1% Ce doped TiO2 thin films as the substrates. Both films exhibited 19% dye removal in 1 hour under 254 nm LED light irradiation whereas the dye removal efficiencies were 36% and 29%, respectively, in 1 hour under 365 nm LED light irradiation.